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以棉属四个栽培棉种进行种间杂交,产生(亚洲棉×草棉)和(陆地棉×海岛棉)2个二元杂种F1及其[(亚洲棉×草棉)×(陆地棉×海岛棉)]四元杂种F1,观察和测定4个栽培棉种及其2个二元杂种F1和四元杂种F1的花粉母细胞(PMC)减数分裂的染色体行为及其花粉生活力,以研究4个栽培棉种间的亲缘关系和进化关系。结果表明,二元杂种(亚洲棉×草棉)F1的PMC减数分裂中期Ⅰ出现一个四体环,其余为二价体,染色体构型为2n=26=11Ⅱ+1Ⅳ;花粉生活力的测定表明,(亚洲棉×草棉)F1可育型花粉为50.71%,表现为典型的配子半不育特性,说明两个二倍体棉种间发生一次染色体易位。(陆地棉×海岛棉)F1以26个二价体细胞为主,但有少量的单价体、三价体以及四价体,染色体构型为2n=52=0.78Ⅰ+22.24Ⅱ+0.94Ⅲ+0.98Ⅳ。花粉生活力的测定表明,(陆地棉×海岛棉)F1可育型花粉为54.84%,可见2个四倍体棉种间亲缘关系较近,二者之间仅发生了染色体的易位或倒位。而由4个栽培种合成的四元杂种F1,其减数分裂异常,染色体丢失现象普遍,部分染色体不能联会配对,以单价体的形式存在,并出现三价体、四价体、五价体等多价体,染色体构型为2n=52=5.45Ⅰ+14.41Ⅱ+2.44Ⅲ+1.59Ⅳ+0.63Ⅴ+0.15Ⅵ,其可育花粉为6.87%。研究结果表明了4种栽培棉种之间的亲缘关系相对较近,可以通过遗传重组产生综合有4个栽培棉种性状的新种质。
Four hybrid cotton cultivars were used for interspecific hybridization to produce two binary hybrids F1 (asiatic cotton × cottonseed) and (Upland cotton × sea island cotton) and their [(Asiatic cotton × cotton) × (Upland cotton × Island cotton F1 hybrid F1] was used to observe and determine the chromosome behavior and pollen viability of meiosis of pollen mother cells (PMCs) of 4 cultivated cotton cultivars, 2 binary hybrid F1 and 4 hybrid F1, The genetic relationship and evolutionary relationship among four cultivated cotton species were studied. The results showed that there was a four-body ring in metaphase I of PMC and the rest was bivalent, the chromosome configuration was 2n = 26 = 11Ⅱ + 1Ⅳ. The pollen viability The results showed that F1 fertile pollen (Asiatic cotton × cotton plant) was 50.71%, showing typical semi-sterility of gametophyte, indicating a chromosomal translocation between two diploid cotton species. (Upland cotton × sea island cotton) F1 was dominated by 26 bivalent somatic cells with a small amount of monovalent, trivalent and tetravalent chromosomal structures of 2n = 52 = 0.78Ⅰ + 22.24Ⅱ + 0.94Ⅲ + 0.98 Ⅳ. The determination of pollen viability showed that fertile pollens of F1 (upland cotton × sea island cotton) were 54.84%, showing that the two tetraploid cotton species were closely related to each other, with only chromosomal translocation or down Bit. The four-hybrid F1 synthesized by four cultivars had abnormal meiosis, common chromosome loss, some chromosomes could not be paired, and existed in the form of monovalent body, and appeared trivalent, tetravalent, pentavalent The chromosome configuration is 2n = 52 = 5.45Ⅰ + 14.41Ⅱ + 2.44Ⅲ + 1.59Ⅳ + 0.63Ⅴ + 0.15 Ⅵ, and the fertile pollen is 6.87%. The results showed that the genetic relationship among the four cultivated cotton species was relatively close, and new germplasm integrated with the characters of four cultivated cotton varieties could be produced by genetic recombination.